Added a (disabled) implementation of dbg_log()

photon/libc/sys/horizon/init.c

@@ -1,6 +1,7 @@
 #include <magenta/task.h>
 #include <magenta/tunnel.h>
 #include <magenta/bootstrap.h>
+#include <magenta/signals.h>
 #include <magenta/errors.h>
 #include <magenta/handle.h>
 #include <magenta/misc.h>
@@ -13,7 +14,22 @@
 #include "__heap.h"
 #include "__fio.h"
 
+#if 1
 #define dbg_log(...)
+#else
+static void dbg_log(const char *format, ...)
+{
+    char buf[1024];
+
+    va_list arg;
+    va_start(arg, format);
+
+    int r = vsnprintf(buf, sizeof buf, format, arg);
+    va_end(arg);
+
+    mx_console_write(buf, r);
+}
+#endif
 
 static const char **environ = NULL;
 
@@ -166,13 +182,22 @@ static void init_stdio(mx_bootstrap_handle_t *handles, size_t nhandles)
     }
 
     __fio_init(0, 1, 2);
+    dbg_log("** photon: stdio init finished\n");
 }
 
 int __crt_init(mx_handle_t bootstrap)
 {
+    dbg_log("reading bootstrap message from %x\n", bootstrap);
+    mx_signals_t sig = 0;
+    mx_object_wait(bootstrap, MX_TUNNEL_READABLE, 0, &sig);
+    if (!(sig & MX_TUNNEL_READABLE)) {
+        dbg_log("no bootstrap message!\n");
+    }
+
     size_t msg_size = 0;
     size_t nr_handles = 0;
     mx_status_t status = mx_tunnel_read(bootstrap, NULL, 0, NULL, 0, &msg_size, &nr_handles);
+    dbg_log("read bootstrap message\n");
 
     if (status != MX_OK) {
         /* TODO replace with a better error handler */
@@ -211,6 +236,7 @@ int __crt_init(mx_handle_t bootstrap)
 
     init_stdio(start_handles, nr_handles);
 
+    dbg_log("calling main\n");
     int ret = main(msg->args_num, argv);
 
     __crt_run_atexit();